/*
 * Copyright (C) 2008 The Guava Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.collect.testing.testers;

import static com.google.common.collect.testing.features.CollectionFeature.ALLOWS_NULL_QUERIES;
import static com.google.common.collect.testing.features.CollectionFeature.ALLOWS_NULL_VALUES;
import static com.google.common.collect.testing.features.CollectionFeature.FAILS_FAST_ON_CONCURRENT_MODIFICATION;
import static com.google.common.collect.testing.features.CollectionFeature.SUPPORTS_REMOVE;
import static com.google.common.collect.testing.features.CollectionSize.SEVERAL;
import static com.google.common.collect.testing.features.CollectionSize.ZERO;

import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.testing.AbstractCollectionTester;
import com.google.common.collect.testing.WrongType;
import com.google.common.collect.testing.features.CollectionFeature;
import com.google.common.collect.testing.features.CollectionSize;

import java.util.ConcurrentModificationException;
import java.util.Iterator;

import org.junit.Ignore;

/**
 * A generic JUnit test which tests {@code remove} operations on a collection. Can't be invoked
 * directly; please see {@link com.google.common.collect.testing.CollectionTestSuiteBuilder}.
 *
 * @author George van den Driessche
 */
@SuppressWarnings("unchecked") // too many "unchecked generic array creations"
@GwtCompatible
@Ignore // Affects only Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
public class CollectionRemoveTester<E> extends AbstractCollectionTester<E>
{
    @CollectionFeature.Require(SUPPORTS_REMOVE)
    @CollectionSize.Require(absent = ZERO)
    public void testRemove_present()
    {
        int initialSize = collection.size();
        assertTrue("remove(present) should return true", collection.remove(e0()));
        assertEquals(
                "remove(present) should decrease a collection's size by one.",
                initialSize - 1,
                collection.size());
        expectMissing(e0());
    }

    @CollectionFeature.Require({SUPPORTS_REMOVE, FAILS_FAST_ON_CONCURRENT_MODIFICATION})
    @CollectionSize.Require(SEVERAL)
    public void testRemovePresentConcurrentWithIteration()
    {
        try
        {
            Iterator<E> iterator = collection.iterator();
            assertTrue(collection.remove(e0()));
            iterator.next();
            fail("Expected ConcurrentModificationException");
        }
        catch (ConcurrentModificationException expected)
        {
            // success
        }
    }

    @CollectionFeature.Require(SUPPORTS_REMOVE)
    public void testRemove_notPresent()
    {
        assertFalse("remove(notPresent) should return false", collection.remove(e3()));
        expectUnchanged();
    }

    @CollectionFeature.Require({SUPPORTS_REMOVE, ALLOWS_NULL_VALUES})
    @CollectionSize.Require(absent = ZERO)
    public void testRemove_nullPresent()
    {
        collection = getSubjectGenerator().create(createArrayWithNullElement());

        int initialSize = collection.size();
        assertTrue("remove(null) should return true", collection.remove(null));
        assertEquals(
                "remove(present) should decrease a collection's size by one.",
                initialSize - 1,
                collection.size());
        expectMissing((E) null);
    }

    @CollectionFeature.Require(absent = SUPPORTS_REMOVE)
    @CollectionSize.Require(absent = ZERO)
    public void testRemove_unsupported()
    {
        try
        {
            collection.remove(e0());
            fail("remove(present) should throw UnsupportedOperationException");
        }
        catch (UnsupportedOperationException expected)
        {
        }
        expectUnchanged();
        assertTrue("remove(present) should not remove the element", collection.contains(e0()));
    }

    @CollectionFeature.Require(absent = SUPPORTS_REMOVE)
    public void testRemove_unsupportedNotPresent()
    {
        try
        {
            assertFalse(
                    "remove(notPresent) should return false or throw UnsupportedOperationException",
                    collection.remove(e3()));
        }
        catch (UnsupportedOperationException tolerated)
        {
        }
        expectUnchanged();
        expectMissing(e3());
    }

    @CollectionFeature.Require(value = SUPPORTS_REMOVE, absent = ALLOWS_NULL_QUERIES)
    public void testRemove_nullNotSupported()
    {
        try
        {
            assertFalse(
                    "remove(null) should return false or throw NullPointerException",
                    collection.remove(null));
        }
        catch (NullPointerException tolerated)
        {
        }
        expectUnchanged();
    }

    @CollectionFeature.Require({SUPPORTS_REMOVE, ALLOWS_NULL_QUERIES})
    public void testRemove_nullAllowed()
    {
        assertFalse("remove(null) should return false", collection.remove(null));
        expectUnchanged();
    }

    @CollectionFeature.Require(absent = SUPPORTS_REMOVE)
    @CollectionSize.Require(absent = ZERO)
    public void testIteratorRemove_unsupported()
    {
        Iterator<E> iterator = collection.iterator();
        iterator.next();
        try
        {
            iterator.remove();
            fail("iterator.remove() should throw UnsupportedOperationException");
        }
        catch (UnsupportedOperationException expected)
        {
        }
        expectUnchanged();
        assertTrue(collection.contains(e0()));
    }

    @CollectionFeature.Require(SUPPORTS_REMOVE)
    public void testRemove_wrongType()
    {
        try
        {
            assertFalse(collection.remove(WrongType.VALUE));
        }
        catch (ClassCastException tolerated)
        {
        }
        expectUnchanged();
    }
}
